Wire gauge recommendation

[johnm1]

To get the most efficent charging to my batteries, with cost kept in mind, what wire gauge should I use between the batteries and charger?

I have a pair of 6v gc batteries.
They're about 12-15 feet from the charger.
I have a Boondocker 75A charger.
Currently have 6awg wire with very good crimped battery lugs.

Thanks

[johnm1]

Update - got back from the long w/e camping and, well, it was so dang hot that I ran the generator as much as possible to run the A/C so I wasn't able to really test out the 12VDC system. When we came back from a bike ride it was over ~85 deg inside the rv ... ick.

However, when I checked the batteries in the mornings, before firing up the generator, they looked pretty good. And that was with the Maxxair fan at 100% for ~12hrs plus lights, awning in and out a few times due to thunder storms and we had 4 boys and 2 adults.

I didn't get a chance to record voltages during and after charging but it looked good the times I took a reading.

While I understand that I have limited data to go by, I'm very pleased with how it performed when compared to any other rv I've owned. I think with the additional upgrades to the wiring I will be even happier.

Most importantly - we got away from the daily grind and had fun!

Thanks all!

[Bobbo]

I am no expert, but I fall on the crimp side. If something causes the wire to heat up enough, the solder can soften allowing the connection to deteriorate. Maybe unlikely, but so was the tile damage that allowed the space shuttle Columbia to burn up on re-entry.

[johnm1]

Just did some web reading. I didn't realize there was a debate going on around crimp vs solder! Huh, who knew!

http://www.marinewireandcable.com/2013/11/crimping-vs-soldering-marine-cable-and.html

[time2roll]

No need to debate soldered vs crimped again. Just look around for what OEM does.
I crimp mine.

[johnm1]

Mex - crimped connections are better than soldered? Crimped are way easier to do so I have no problems with that. I'm just asking so I can learn.

[MEXICOWANDERER]

I'll merely chip-in with this tidbit...

When I extended the 6 AWG wiring of the 55-ampere WFCO by FOUR FEET EACH LEG UNDER NO CIRCUMSTANCES would the converter go into 14.62volts boost mode. 12.0 volts start up no boost.

Then I chopped off but 6" wire on both legs and grafted 7' of No 4 AWG wire onto both legs. The WFCO now easily drops into boost mode, when voltage is 12.3 at startup.

Working with 30 FEET of wire and there's a debate about using too large of wire? You gotta be ------ me. Consulting books and charts for voltage drop only works if it agrees with reality. The converter is not a static component of the equation. It is reactive. To treat it otherwise is "uneducated guesswork".

No 2 AWG insures a minimal voltage drop ESPECIALLY when crimped terminals are used instead of soldered terminals. Voltage drop is CUMULATIVE and guess what (?), the converter sensing circuit does care. It cares enough to malfunction if it sees enough assumptive error in accumulated voltage drop.

This isn't jacks, or slideout load calculation, it is the reality of working with a yes/no sensitive reactive circuit.

And for criminy's sake, INCLUDE terminations voltage drop in your bookworm calculations of circular mils times distance. Terminations AT THE BATTERIES also enters the picture. Corrosion and oxidation that does not perceptibly degrade motor performance will destroy your sanity when reactive voltage sensing enters the picture. A large converter raises it's leg and ----- on the relative load of jacks or sildeout motors.

I did not recommend 2AWG for fun. The entire package including ampacity of terminations is there for a reason.

Reality is a rude taskmaster. It ridicules theoretical assumptions.

[time2roll]

grizzzman wrote:
Once again what is your point?

#6 and #4 have the cross-section of #2 not 2/0.
Adding diameter of parallel conductors is not the proper way to compare equivalent sizes for resistance or ampacity.

[johnm1]

A. Agreed!
B. Yep
C. Great!

Can't wait until Friday - 1st trip of the year and with the new rig!!!

[grizzzman]

johnm1 wrote:

grizzzman wrote:
You still here johnm1?

Yep - haven't lost me yet. Well, I do fade in and out when y'all talk in terms I don't understand!

It sounds like I'm not going to hurt anything, at least in the short term, so I'm going to leave the rig as is for this 1st trip, it's only 4 days. Hopefully it'll be enough time to see what works and what doesn't. What I mean by work/no work is ... "wholly cwap this is a pain in the arss to deal with" or, "Son of a biscuit, we ran out of power the 1st night" or, "no problem - piece of cake". I'll check voltages while charging, if I need to charge, to see what it's doing. I've got lot's of soon to be cold beer, firewood and a great wife waiting in the wings! I suppose I should mention the 2 boys and their friends that we somehow invited!

Before our big trip this July, I'll replace the battery cables with 2 gauge and add 2 more batteries. The notion of not draining the batteries as far down and less often makes a great deal of sense to me. I'll look to see how hard it'd be to move the charger closer to the batteries at that time.

What gauge should I use between the batteries for the series connections? Same 2 gauge or ???

Thanks again!!

A. (And this is most important) Fun comes first!
B. As I remember, you are a minimalist power user so you may not need to charge camping(this trip). (And using 80% once in a while is no big deal.)
C. The way you are currently using the batteries #2 will be fine.

[johnm1]

grizzzman wrote:
You still here johnm1?

Yep - haven't lost me yet. Well, I do fade in and out when y'all talk in terms I don't understand!

It sounds like I'm not going to hurt anything, at least in the short term, so I'm going to leave the rig as is for this 1st trip, it's only 4 days. Hopefully it'll be enough time to see what works and what doesn't. What I mean by work/no work is ... "wholly cwap this is a pain in the arss to deal with" or, "Son of a biscuit, we ran out of power the 1st night" or, "no problem - piece of cake". I'll check voltages while charging, if I need to charge, to see what it's doing. I've got lot's of soon to be cold beer, firewood and a great wife waiting in the wings! I suppose I should mention the 2 boys and their friends that we somehow invited!

Before our big trip this July, I'll replace the battery cables with 2 gauge and add 2 more batteries. The notion of not draining the batteries as far down and less often makes a great deal of sense to me. I'll look to see how hard it'd be to move the charger closer to the batteries at that time.

What gauge should I use between the batteries for the series connections? Same 2 gauge or ???

Thanks again!!

[grizzzman]

smkettner wrote:
Wire size can be measured in several ways. We could speak of a wire’s diameter, but since its really the cross-sectional area that matters most regarding the flow of electrons, we are better off designating wire size in terms of area.

http://www.allaboutcircuits.com/textbook/direct-current/chpt-12/conductor-size/

"For electrical conductor sizing, the American Wire Gauge (AWG), also known as the Brown and Sharpe (B&S) gauge, is the measurement system of choice".

Out of the very article you posted. Once again what is your point?

[Calkidd]

EsoxLucius wrote:

Calkidd wrote:
Wire size graph

What a mess of BBCodes! And that graph is pathetic. Use a real calculator.

Thanks for the rude comment. The link was suppose to go to a image that shows amerpage and length vs. wire size.

[time2roll]

Wire size can be measured in several ways. We could speak of a wire’s diameter, but since its really the cross-sectional area that matters most regarding the flow of electrons, we are better off designating wire size in terms of area.

http://www.allaboutcircuits.com/textbook/direct-current/chpt-12/conductor-size/

[grizzzman]

You still here johnm1?